From time immemorial, cocoons formed by silkworms have been highly valued as the source of raw silk for silks and many different technical developments and improvements have been made to obtain silks of high quality and hence high quality raw silk. However, these technical developments and improvements have been directed for the most part to the processing techniques of raw silk such as degumming, weaving and dyeing techniques, and there have been few instances in which the cocoons themselves were valued as materials of folk handicraft articles and industrial art objects. Namely, reality is that there has been developed no technique of processing the cocoon itself to incorporate a sounding object in the cocoon or coloring or imparting the desired color to the cocoon.
However, since the cocoons possess a satisfactory beauty or attractive feature as natural objects, if a sounding device is inserted into the cocoons or the cocoons are colored, it is possible to process the cocoons as such to produce a variety of highly tasteful articles which utilize the properties of the cocoons.